CALCULATIONS OF THE ELECTROMAGNETIC PROCESSES WHEN A 110 kV POWER LINE WITH UNLOADED TRANSFORMERS IS SWITCHED UNDER INCOMPLETE-PHASE CONDITIONS

摘要

The electromagnetic processes that occur when opening and closing a high-voltage circuit-breaker at the beginning of a power line with an unloaded transformer are investigated. At the instants when a power line is switched on and off, it may happen that all its phases are not opened and closed simultaneously. There may be situations when two phases are opened and one phase is closed, and when two phases are closed and one phase is opened. The overvoltages that occur under these conditions are called ferroresonance overvoltages. The incomplete-phase conditions are analysed taking the skin-effect and the corona into account. The results obtained enable a protective device to be selected and the effect due to the current through an overvoltage limiter to be evaluated.